Definition of Muscular atrophy, post-polio (PPMA)

Muscular atrophy, post-polio (PPMA): Late muscle wasting that occurs as part of the post-polio syndrome (PPS), a constellation of symptoms and signs that appear belatedly, from 20 to 40 years, after the initial polio infection and at least 10 years after what was once thought to be the "recovery" from polio.

PPS is no small problem. It is estimated that 1.63 million Americans were struck by polio in the epidemics of the 1940's, 50's, and early 60's and that 440,000 of the survivors have suffered and continue to suffer the effects of PPS.

The typical features of PPS include unaccustomed weakness, muscle fatigue (and sometimes "central" fatigue), pain, breathing and/or swallowing difficulties, sleep disorders, muscle twitching (fasciculations) and gastrointestinal problems. The muscle problems in PPS can occur in previously-affected muscles or in muscles that were previously thought not to be muscles that were not affected at onset of the polio.

The onset of PPS is usually gradual, over a period of years, but sometimes abrupt, with major loss of function suffered over several months or a couple of years. This process seems often to start after a physical or emotional trauma, an illness or accident.

The diagnosis of PPS is made by history, by clinical findings, and by ruling out other diseases that may mimic PPS. There are no specific tests to provide unquestionable confirmation of the diagnosis of PPS.

The general rule is that those who were most seriously affected by the virus at initial onset and made the best recovery come to suffer the worst PPS symptoms years later.

No clearcut cause for PPS has been found. There is known to be a failure at the neuromuscular junction (the place where nerves meet muscles). One idea put forth to explain PPS is that nerves and muscles that have had to overwork prematurely fail, but this is unproven. There is also known to be impairment in the production of certain hormones and neurotransmitters, but whether these changes are the cause of PPS or the effect of it is unknown.

Polio survivors -- such as Franklin D. Roosevelt, Itzhak Perlman, Joni Mitchell, and Alan Alda -- tend to be hard-driving, type-A personalities (as compared to nondisabled control subjects). And the more driven polio survivors tend to have more PPS symptoms.

The treatment of PPS including PPMA that is recommended by some authorities is therefore to slow down and try to conserve strength and energy. (This may not be entirely practical advise if the patient is the President of the United States or one of the world's greatest concert violinists).